To reduce the pressure in an aggregate of reinforcing materials, to therefore increase the infiltrating force of Mg molten metal and to efficiently obtain an Mg matrix composite material by substituting the inside of an aggregate of reinforcing materials with a gas to be brought into reaction with Mg and to form a solid, limiting the flown of the gas into the aggregate and infiltrating the Mg molten metal therein.
Aluminum borate or the like and SiO2 particles are kneaded and baked to obtain a preform of an aggregate of reinforcing materials. One face of the preform 1 is coated with suspension of SiO2 particles as an infiltration auxiliary agent. The preform 1 is placed at the bottom of a crucible 2 with the face to be applied with SiO2 as the upper side, and a pure Mg ingot is placed thereon. The crucible 2 is set to the inside of an electric resistance furnace 5 and is heated by an electric resistance heater 8 in a CO2+0.3% SF6 atmosphere. In the process of the heating, the inside of the preform 1 is substituted with a gaseous mixture of CO2 and SF6, and by the melting of pure Mg, the preform 1 is formed into a closed state. By the effect of the infiltration auxiliary agent, the pure Mg molten metal 4 spontaneously infiltrates into the preform 1 to form the composite material. As for Mg, Mg alloys may be used.
KANEDA HIROMITSU
SANO YOSHINOBU
